Organic light-emitting display device with frit seal and reinforcing structure

ABSTRACT

Disclosed is an organic light-emitting display device in which the substrate and the encapsulation substrate are attached to each other by using a frit. The organic light-emitting display device includes a first substrate including a pixel region in which an organic light-emitting diode is formed, and a non-pixel region. The organic light-emitting diode includes an organic light-emitting layer between a first electrode and a second electrode. A second substrate attached to the first substrate. A frit is provided between the non-pixel region of the first substrate and the second substrate to attach the first substrate and the second substrate. A reinforcement material of resin is formed outside the frit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Patent Application No.2006-06148, filed on Jan. 20, 2006, in the Korean Intellectual PropertyOffice, the disclosure of which is incorporated herein by reference inits entirety. This application is related to and incorporates herein byreference the entire contents of the following concurrently filedapplications:

Application Title Filing Date No. ORGANIC LIGHT-EMITTING Sep. 29, 200611/541,055 DISPLAY DEVICE AND METHOD OF FABRICATING THE SAME ORGANICLIGHT-EMITTING Sep. 29, 2006 11/529,914 DISPLAY DEVICE AND METHOD OFMANUFAC- TURING THE SAME ORGANIC LIGHT EMITTING Sep. 29, 2006 11/541,139DISPLAY DEVICE ORGANIC LIGHT EMITTING Sep. 29, 2006 11/540,150 DISPLAYDEVICE METHOD OF FABRICATING THE SAME ORGANIC LIGHT EMITTING Sep. 29,2006 11/541,009 DISPLAY AND METHOD OF FABRICATING THE SAME ORGANICLIGHT-EMITTING Sep. 29, 2006 11/540,151 DISPLAY DEVICE WITH FRIT SEALAND REINFORCING STRUCTURE BONDED TO FRAME METHOD FOR PACKAGING Sep. 29,2006 11/529,910 ORGANIC LIGHT-EMITTING DISPLAY WITH FRIT SEAL ANDREINFORCING STRUCTURE METHOD FOR PACKAGING Sep. 29, 2006 11/540,084ORGANIC LIGHT EMITTING DISPLAY WITH FRIT SEAL AND REINFORCING STURUTUREORGANIC LIGHT-EMITTING Sep. 29, 2006 11/541,048 DISPLAY DEVICE AND THEPREPARATION METHOD OF THE SAME ORGANIC LIGHT EMITTING Sep. 29, 200611/540,021 DISPLAY AND FABRICATING METHOD OF THE SAME ORGANICLIGHT-EMITTING Sep. 29, 2006 11/540,021 DISPLAY AND METHOD OF MAKING THESAME ORGANIC LIGHT EMITTING Sep. 29, 2006 11/540,024 DISPLAY ANDFABRICATING METHOD OF THE SAME ORGANIC LIGHT EMITTING Sep. 29, 200611/529,995 DISPLAY DEVICE AND MANUFACTURING METHOD THEREOF ORGANICLIGHT-EMITTING Sep. 29, 2006 11/540,157 DISPLAY DEVICE AND MANUFACTURINGMETHOD OF THE SAME ORGANIC LIGHT EMITTING Sep. 29, 2006 11/540,149DISPLAY AND FABRICATING METHOD OF THE SAME ORGANIC LIGHT EMITTING Sep.29, 2006 11/529,916 DISPLAY AND METHOD OF FABRICATING THE SAME ORGANICLIGHT EMITTING Sep. 29, 2006 11/529,891 DISPLAY DEVICE METHOD OFFABRICATING THE SAME ORGANIC LIGHT EMITTING Sep. 29, 2006 11/540,103DISPLAY AND METHOD OF FABRICATING THE SAME

BACKGROUND

1. Field of the Invention

The present invention relates to organic light-emitting display devicesand, more particularly, to packaging such devices.

2. Discussion of Related Art

An organic light-emitting display device is one of the flat paneldisplays in which an electron injected to one electrode and a holeinjected to the other electrode bind to each other in an organiclight-emitting layer when the organic light-emitting layer is arrangedbetween facing electrodes and a voltage is applied to both electrodes,wherein, when luminescent molecules of the light-emitting layer areexcited by the binding of the electron and the hole, energy is emittedby returning to a ground state, and then converted into the light. Theorganic light-emitting display devices exhibiting such a light-emissionprinciple has drawn attention as a next-generation display since theyare excellent in visibility, and they may be also manufactured in alight weight and thin shape and driven at a low voltage. U.S. Pat. No.6,998,776 B2 discloses that an organic light-emitting display includes afirst substrate plate, a second substrate plate and a frit connectingthe plates.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

One aspect of the invention provides an organic light-emitting displaydevice, which may comprise: a first substrate; a second substrate placedover the first substrate; an array of organic light-emitting pixelsinterposed between the first and second substrates; a frit sealinterposed between the first substrate and the second substrate whilesurrounding the array, wherein the frit seal, the first substrate andthe second substrate in combination define an enclosed space in whichthe array is located; and a structure comprising a portion interposedbetween the first and second substrates, wherein the structure islocated outside the enclosed space. The structure may improve structuralstrength of the device.

In the foregoing device, the portion of the structure may contact thefrit seal. The structure may not contact the frit seal. The structuremay comprise another portion that is not interposed between the firstand second substrates. The structure may comprise a cured polymericresin. The structure may comprise at least one selected from the groupconsisting of cyanoacrylate, acrylate, epoxy, acrylate, urethaneacrylate and cured polymers of two or more of the foregoing. Thestructure substantially surrounds the frit seal. The structure may beconfigured to improve sealing of the enclosed space.

Still in the forgoing device, the frit seal may be connected to thefirst substrate via a material formed between the frit seal and thefirst substrate. The structure may contact the first substrate. Thestructure may be connected to the first substrate via another materialbetween the structure and the first substrate. The first substrate maycomprise a first edge and the second substrate may comprise a secondedge extending generally along the first edges, and wherein the fritseal may extend along the first and second edge while apart from thefirst and second edges, wherein the structure may contact the first andsecond substrates, and extends along the first and second edges. Thestructure may contact first and second edges. The first substratecomprises a first edge and the frit seal may be apart from the firstedge from about 0.3 to about 0.7 mm. The first substrate may comprise afront surface of the device, the front surface facing away from thesecond substrate, and wherein the structure may provide a side surfaceof the device. The side surface may be substantially planar. The fritseal may comprise one or more materials selected from the groupconsisting of magnesium oxide (MgO), calcium oxide (CaO), barium oxide(BaO), lithium oxide (Li₂O), sodium oxide (Na₂O), potassium oxide (K₂O),boron oxide (B₂O₃), vanadium oxide (V₂O₅), zinc oxide (ZnO), telluriumoxide (TeO₂), aluminum oxide (Al₂O₃), silicon dioxide (SiO₂), lead oxide(PbO), tin oxide (SnO), phosphorous oxide (P₂O₅), ruthenium oxide(Ru₂O), rubidium oxide (Rb₂O), rhodium oxide (Rh₂O), ferrite oxide(Fe₂O₃), copper oxide (CuO), titanium oxide (TiO₂), tungsten oxide(WO₃), bismuth oxide (Bi₂O₃), antimony oxide (Sb₂O₃), lead-borate glass,tin-phosphate glass, vanadate glass, and borosilicate.

Another aspect of the invention provides a method of making an organiclight-emitting display device, which may comprises: providing anunfinished device comprising a first substrate, a second substrateplaced over the first substrate, an array of organic light-emittingpixels interposed between the first and second substrates, and a fritseal interposed between the first substrate and the second substratewhile surrounding the array, wherein the frit seal, the first substrateand the second substrate in combination define an enclosed space, inwhich the array is located; and forming a structure outside the enclosedspace such that the structure comprises a portion interposed between thefirst and second substrates.

In the foregoing method, forming may comprise placing a curable liquidmaterial in the vicinity of the frit seal while not contacting the fritseal, whereby at least part of the curable liquid material mayspontaneously move toward the frit seal by capillary action, andsolidifying the curable liquid material, thereby forming the structure.The first substrate may comprise a first surface and the secondsubstrate may comprise a second surface facing the first surface,wherein the first surface, second surface and the frit seal may togetherdefine a gap outside the enclosed space, and wherein forming thestructure may comprise applying a curable material into the gap. Thecurable material may be liquid, and the curable material spontaneouslymoves toward the frit seal when being applied into the gap. Forming thestructure may further comprise curing the curable material by activatinga curing process of the curable material. The gap may be formedthroughout the periphery of the unfinished device, and wherein formingthe structure may comprise applying the curable material into the gapsubstantially throughout the periphery of the unfinished device.

Still in the foregoing method, forming the structure may compriseplacing a curable material in vicinity of the frit seal, and curing thecurable material. Forming the structure may comprise providing adispenser containing the curable material, applying the curable materialonto a surface of the unfinished device using the dispenser, whereby aportion of the curable material is formed between the first and secondsubstrates, and curing the curable material. Forming the structure maycomprise providing a medium retaining the curable material, applying thecurable material on a surface of the unfinished device using the medium,whereby a portion of the curable material is formed between the firstand second substrates, and curing the curable material. Forming thestructure may comprise providing a curable material in liquid, dipping aperiphery of the unfinished device into the liquid curable material,whereby a portion of the liquid curable material is formed between thefirst and second substrates; and curing the curable material.

Still another aspect of the present invention provides an organiclight-emitting display device further including a reinforcement materialof resin in the outside of a frit.

Further aspect of the present invention provides an organiclight-emitting display device including a first substrate comprising apixel region in which an organic light-emitting diode or pixels isformed in a surface thereof, and a non-pixel region, the organiclight-emitting diode comprising an organic light-emitting layer betweena first electrode and a second electrode; a second substrate coalescedto one region including the pixel region of the substrate; a fritprovided between the non-pixel region of the first substrate and thesecond substrate and attaching the first substrate and the secondsubstrate to each other; and a reinforcement material of resin formedoutside of the frit.

Still further aspect of the present invention provides a method forpreparing an organic light-emitting display device, including asubstrate including an organic light-emitting diode, and anencapsulation substrate for encapsulating at least a pixel region of thesubstrate, the method including the first step of applying and sinteringa frit paste to an edge region of the encapsulation substrate; thesecond step of coalescing the substrate and the encapsulation substrateto each other; the third step of melting the frit to attach thesubstrate and the encapsulation substrate to each other by irradiating alaser or an infrared ray to the frit between the substrate and theencapsulation substrate, both coalesced to each other; and the fourthstep of injecting the reinforcement material into the outside of thefrit between the substrate and the encapsulation substrate. The organiclight-emitting diode may be completely protected from the open air bycompletely coalescing a substrate and a encapsulation substrate to eachother using a frit and solving brittleness of the organic light-emittingdisplay device when the frit is used herein.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects and advantages of the invention will becomeapparent and more readily appreciated from the following description ofembodiments, taken in conjunction with the accompanying drawings.

FIG. 1 is a cross-sectional view showing an organic light-emittingdisplay device.

FIG. 2 is a plan view showing an organic light-emitting display deviceaccording to one embodiment of the present invention.

FIGS. 3 a and 3 b are cross-sectional views showing an organiclight-emitting display device according to one embodiment of the presentinvention, respectively.

FIGS. 4 a to 4 d are cross-sectional views showing a process forpreparing an organic light-emitting display device according to anembodiment of the present invention.

FIGS. 5 a to 5 d show a process for packaging an organic light-emittingdisplay device according to an embodiment of the present invention.

FIG. 6 is a cross-sectional view showing an organic light-emittingdisplay device according to another embodiment of the present invention.

FIG. 7A is a schematic exploded view of a passive matrix type organiclight emitting display device in accordance with one embodiment.

FIG. 7B is a schematic exploded view of an active matrix type organiclight emitting display device in accordance with one embodiment.

FIG. 7C is a schematic top plan view of an organic light emittingdisplay in accordance with one embodiment.

FIG. 7D is a cross-sectional view of the organic light emitting displayof FIG. 7C, taken along the line d-d.

FIG. 7E is a schematic perspective view illustrating mass production oforganic light emitting devices in accordance with one embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, various embodiments of the present invention will bedescribed in detail. However, it would be appreciated by those skilledin the art that modifications and changes might be made in theembodiments without departing from the principles and spirit of theinvention. For example, changes of materials constituting an organiclight-emitting layer, absence of color-changing layers or green-barrierlayers, and changes of height and width may be easily made by thoseskilled in the art.

An organic light emitting display (OLED) is a display device comprisingan array of organic light emitting diodes. Organic light emitting diodesare solid state devices which include an organic material and areadapted to generate and emit light when appropriate electricalpotentials are applied.

OLEDs can be generally grouped into two basic types dependent on thearrangement with which the stimulating electrical current is provided.FIG. 7A schematically illustrates an exploded view of a simplifiedstructure of a passive matrix type OLED 1000. FIG. 7B schematicallyillustrates a simplified structure of an active matrix type OLED 1001.In both configurations, the OLED 1000, 1001 includes OLED pixels builtover a substrate 1002, and the OLED pixels include an anode 1004, acathode 1006 and an organic layer 1010. When an appropriate electricalcurrent is applied to the anode 1004, electric current flows through thepixels and visible light is emitted from the organic layer.

Referring to FIG. 7A, the passive matrix OLED (PMOLED) design includeselongate strips of anode 1004 arranged generally perpendicular toelongate strips of cathode 1006 with organic layers interposedtherebetween. The intersections of the strips of cathode 1006 and anode1004 define individual OLED pixels where light is generated and emittedupon appropriate excitation of the corresponding strips of anode 1004and cathode 1006. PMOLEDs provide the advantage of relatively simplefabrication.

Referring to FIG. 7B, the active matrix OLED (AMOLED) includes localdriving circuits 1012 arranged between the substrate 1002 and an arrayof OLED pixels. An individual pixel of AMOLEDs is defined between thecommon cathode 1006 and an anode 1004, which is electrically isolatedfrom other anodes. Each driving circuit 1012 is coupled with an anode1004 of the OLED pixels and further coupled with a data line 1016 and ascan line 1018. In embodiments, the scan lines 1018 supply scan signalsthat select rows of the driving circuits, and the data lines 1016 supplydata signals for particular driving circuits. The data signals and scansignals stimulate the local driving circuits 1012, which excite theanodes 1004 so as to emit light from their corresponding pixels.

In the illustrated AMOLED, the local driving circuits 1012, the datalines 1016 and scan lines 1018 are buried in a planarization layer 1014,which is interposed between the pixel array and the substrate 1002. Theplanarization layer 1014 provides a planar top surface on which theorganic light emitting pixel array is formed. The planarization layer1014 may be formed of organic or inorganic materials, and formed of twoor more layers although shown as a single layer. The local drivingcircuits 1012 are typically formed with thin film transistors (TFT) andarranged in a grid or array under the OLED pixel array. The localdriving circuits 1012 may be at least partly made of organic materials,including organic TFT. AMOLEDs have the advantage of fast response timeimproving their desirability for use in displaying data signals. Also,AMOLEDs have the advantages of consuming less power than passive matrixOLEDs.

Referring to common features of the PMOLED and AMOLED designs, thesubstrate 1002 provides structural support for the OLED pixels andcircuits. In various embodiments, the substrate 1002 can comprise rigidor flexible materials as well as opaque or transparent materials, suchas plastic, glass, and/or foil. As noted above, each OLED pixel or diodeis formed with the anode 1004, cathode 1006 and organic layer 1010interposed therebetween. When an appropriate electrical current isapplied to the anode 1004, the cathode 1006 injects electrons and theanode 1004 injects holes. In certain embodiments, the anode 1004 andcathode 1006 are inverted; i.e., the cathode is formed on the substrate1002 and the anode is opposingly arranged.

Interposed between the cathode 1006 and anode 1004 are one or moreorganic layers. More specifically, at least one emissive or lightemitting layer is interposed between the cathode 1006 and anode 1004.The light emitting layer may comprise one or more light emitting organiccompounds. Typically, the light emitting layer is configured to emitvisible light in a single color such as blue, green, red or white. Inthe illustrated embodiment, one organic layer 1010 is formed between thecathode 1006 and anode 1004 and acts as a light emitting layer.Additional layers, which can be formed between the anode 1004 andcathode 1006, can include a hole transporting layer, a hole injectionlayer, an electron transporting layer and an electron injection layer.

Hole transporting and/or injection layers can be interposed between thelight emitting layer 1010 and the anode 1004. Electron transportingand/or injecting layers can be interposed between the cathode 1006 andthe light emitting layer 1010. The electron injection layer facilitatesinjection of electrons from the cathode 1006 toward the light emittinglayer 1010 by reducing the work function for injecting electrons fromthe cathode 1006. Similarly, the hole injection layer facilitatesinjection of holes from the anode 1004 toward the light emitting layer1010. The hole and electron transporting layers facilitate movement ofthe carriers injected from the respective electrodes toward the lightemitting layer.

In some embodiments, a single layer may serve both electron injectionand transportation functions or both hole injection and transportationfunctions. In some embodiments, one or more of these layers are lacking.In some embodiments, one or more organic layers are doped with one ormore materials that help injection and/or transportation of thecarriers. In embodiments where only one organic layer is formed betweenthe cathode and anode, the organic layer may include not only an organiclight emitting compound but also certain functional materials that helpinjection or transportation of carriers within that layer.

There are numerous organic materials that have been developed for use inthese layers including the light emitting layer. Also, numerous otherorganic materials for use in these layers are being developed. In someembodiments, these organic materials may be macromolecules includingoligomers and polymers. In some embodiments, the organic materials forthese layers may be relatively small molecules. The skilled artisan willbe able to select appropriate materials for each of these layers in viewof the desired functions of the individual layers and the materials forthe neighboring layers in particular designs.

In operation, an electrical circuit provides appropriate potentialbetween the cathode 1006 and anode 1004. This results in an electricalcurrent flowing from the anode 1004 to the cathode 1006 via theinterposed organic layer(s). In one embodiment, the cathode 1006provides electrons to the adjacent organic layer 1010. The anode 1004injects holes to the organic layer 1010. The holes and electronsrecombine in the organic layer 1010 and generate energy particles called“excitons.” The excitons transfer their energy to the organic lightemitting material in the organic layer 1010, and the energy is used toemit visible light from the organic light emitting material. Thespectral characteristics of light generated and emitted by the OLED1000, 1001 depend on the nature and composition of organic molecules inthe organic layer(s). The composition of the one or more organic layerscan be selected to suit the needs of a particular application by one ofordinary skill in the art.

OLED devices can also be categorized based on the direction of the lightemission. In one type referred to as “top emission” type, OLED devicesemit light and display images through the cathode or top electrode 1006.In these embodiments, the cathode 1006 is made of a material transparentor at least partially transparent with respect to visible light. Incertain embodiments, to avoid losing any light that can pass through theanode or bottom electrode 1004, the anode may be made of a materialsubstantially reflective of the visible light. A second type of OLEDdevices emits light through the anode or bottom electrode 1004 and iscalled “bottom emission” type. In the bottom emission type OLED devices,the anode 1004 is made of a material which is at least partiallytransparent with respect to visible light. Often, in bottom emissiontype OLED devices, the cathode 1006 is made of a material substantiallyreflective of the visible light. A third type of OLED devices emitslight in two directions, e.g. through both anode 1004 and cathode 1006.Depending upon the direction(s) of the light emission, the substrate maybe formed of a material which is transparent, opaque or reflective ofvisible light.

In many embodiments, an OLED pixel array 1021 comprising a plurality oforganic light emitting pixels is arranged over a substrate 1002 as shownin FIG. 7C. In embodiments, the pixels in the array 1021 are controlledto be turned on and off by a driving circuit (not shown), and theplurality of the pixels as a whole displays information or image on thearray 1021. In certain embodiments, the OLED pixel array 1021 isarranged with respect to other components, such as drive and controlelectronics to define a display region and a non-display region. Inthese embodiments, the display region refers to the area of thesubstrate 1002 where OLED pixel array 1021 is formed. The non-displayregion refers to the remaining areas of the substrate 1002. Inembodiments, the non-display region can contain logic and/or powersupply circuitry. It will be understood that there will be at leastportions of control/drive circuit elements arranged within the displayregion. For example, in PMOLEDs, conductive components will extend intothe display region to provide appropriate potential to the anode andcathodes. In AMOLEDs, local driving circuits and data/scan lines coupledwith the driving circuits will extend into the display region to driveand control the individual pixels of the AMOLEDs.

One design and fabrication consideration in OLED devices is that certainorganic material layers of OLED devices can suffer damage or accelerateddeterioration from exposure to water, oxygen or other harmful gases.Accordingly, it is generally understood that OLED devices be sealed orencapsulated to inhibit exposure to moisture and oxygen or other harmfulgases found in a manufacturing or operational environment. FIG. 7Dschematically illustrates a cross-section of an encapsulated OLED device1011 having a layout of FIG. 7C and taken along the line d-d of FIG. 7C.In this embodiment, a generally planar top plate or substrate 1061engages with a seal 1071 which further engages with a bottom plate orsubstrate 1002 to enclose or encapsulate the OLED pixel array 1021. Inother embodiments, one or more layers are formed on the top plate 1061or bottom plate 1002, and the seal 1071 is coupled with the bottom ortop substrate 1002, 1061 via such a layer. In the illustratedembodiment, the seal 1071 extends along the periphery of the OLED pixelarray 1021 or the bottom or top plate 1002, 1061.

In embodiments, the seal 1071 is made of a frit material as will befurther discussed below. In various embodiments, the top and bottomplates 1061, 1002 comprise materials such as plastics, glass and/ormetal foils which can provide a barrier to passage of oxygen and/orwater to thereby protect the OLED pixel array 1021 from exposure tothese substances. In embodiments, at least one of the top plate 1061 andthe bottom plate 1002 are formed of a substantially transparentmaterial.

To lengthen the life time of OLED devices 1011, it is generally desiredthat seal 1071 and the top and bottom plates 1061, 1002 provide asubstantially non-permeable seal to oxygen and water vapor and provide asubstantially hermetically enclosed space 1081. In certain applications,it is indicated that the seal 1071 of a frit material in combinationwith the top and bottom plates 1061, 1002 provide a barrier to oxygen ofless than approximately 10⁻³ cc/m²-day and to water of less than 10⁻⁶g/m²-day. Given that some oxygen and moisture can permeate into theenclosed space 1081, in some embodiments, a material that can take upoxygen and/or moisture is formed within the enclosed space 1081.

The seal 1071 has a width W, which is its thickness in a directionparallel to a surface of the top or bottom substrate 1061, 1002 as shownin FIG. 7D. The width varies among embodiments and ranges from about 300μm to about 3000 μm, optionally from about 500 μm to about 1500 μm.Also, the width may vary at different positions of the seal 1071. Insome embodiments, the width of the seal 1071 may be the largest wherethe seal 1071 contacts one of the bottom and top substrate 1002, 1061 ora layer formed thereon. The width may be the smallest where the seal1071 contacts the other. The width variation in a single cross-sectionof the seal 1071 relates to the cross-sectional shape of the seal 1071and other design parameters.

The seal 1071 has a height H, which is its thickness in a directionperpendicular to a surface of the top or bottom substrate 1061, 1002 asshown in FIG. 7D. The height varies among embodiments and ranges fromabout 2 μm to about 30 μm, optionally from about 10 μm to about 15 μm.Generally, the height does not significantly vary at different positionsof the seal 1071. However, in certain embodiments, the height of theseal 1071 may vary at different positions thereof.

In the illustrated embodiment, the seal 1071 has a generally rectangularcross-section. In other embodiments, however, the seal 1071 can haveother various cross-sectional shapes such as a generally squarecross-section, a generally trapezoidal cross-section, a cross-sectionwith one or more rounded edges, or other configuration as indicated bythe needs of a given application. To improve hermeticity, it isgenerally desired to increase the interfacial area where the seal 1071directly contacts the bottom or top substrate 1002, 1061 or a layerformed thereon. In some embodiments, the shape of the seal can bedesigned such that the interfacial area can be increased.

The seal 1071 can be arranged immediately adjacent the OLED array 1021,and in other embodiments, the seal 1071 is spaced some distance from theOLED array 1021. In certain embodiment, the seal 1071 comprisesgenerally linear segments that are connected together to surround theOLED array 1021. Such linear segments of the seal 1071 can extend, incertain embodiments, generally parallel to respective boundaries of theOLED array 1021. In other embodiment, one or more of the linear segmentsof the seal 1071 are arranged in a non-parallel relationship withrespective boundaries of the OLED array 1021. In yet other embodiments,at least part of the seal 1071 extends between the top plate 1061 andbottom plate 1002 in a curvilinear manner.

As noted above, in certain embodiments, the seal 1071 is formed using afrit material or simply “frit” or glass frit,” which includes fine glassparticles. The frit particles includes one or more of magnesium oxide(MgO), calcium oxide (CaO), barium oxide (BaO), lithium oxide (Li₂O),sodium oxide (Na₂O), potassium oxide (K₂O), boron oxide (B₂O₃), vanadiumoxide (V₂O₅), zinc oxide (ZnO), tellurium oxide (TeO₂), aluminum oxide(Al₂O₃), silicon dioxide (SiO₂), lead oxide (PbO), tin oxide (SnO),phosphorous oxide (P₂O₅), ruthenium oxide (Ru₂O), rubidium oxide (Rb₂O),rhodium oxide (Rh₂O), ferrite oxide (Fe₂O₃), copper oxide (CuO),titanium oxide (TiO₂), tungsten oxide (WO₃), bismuth oxide (Bi₂O₃),antimony oxide (Sb₂O₃), lead-borate glass, tin-phosphate glass, vanadateglass, and borosilicate, etc. In embodiments, these particles range insize from about 2 μm to about 30 μm, optionally about 5 μm to about 10μm, although not limited only thereto. The particles can be as large asabout the distance between the top and bottom substrates 1061, 1002 orany layers formed on these substrates where the frit seal 1071 contacts.

The frit material used to form the seal 1071 can also include one ormore filler or additive materials. The filler or additive materials canbe provided to adjust an overall thermal expansion characteristic of theseal 1071 and/or to adjust the absorption characteristics of the seal1071 for selected frequencies of incident radiant energy. The filler oradditive material(s) can also include inversion and/or additive fillersto adjust a coefficient of thermal expansion of the frit. For example,the filler or additive materials can include transition metals, such aschromium (Cr), iron (Fe), manganese (Mn), cobalt (Co), copper (Cu),and/or vanadium. Additional materials for the filler or additivesinclude ZnSiO₄, PbTiO₃, ZrO₂, eucryptite.

In embodiments, a frit material as a dry composition contains glassparticles from about 20 to 90 about wt %, and the remaining includesfillers and/or additives. In some embodiments, the frit paste containsabout 10-30 wt % organic materials and about 70-90% inorganic materials.In some embodiments, the frit paste contains about 20 wt % organicmaterials and about 80 wt % inorganic materials. In some embodiments,the organic materials may include about 0-30 wt % binder(s) and about70-100 wt % solvent(s). In some embodiments, about 10 wt % is binder(s)and about 90 wt % is solvent(s) among the organic materials. In someembodiments, the inorganic materials may include about 0-10 wt %additives, about 20-40 wt % fillers and about 50-80 wt % glass powder.In some embodiments, about 0-5 wt % is additive(s), about 25-30 wt % isfiller(s) and about 65-75 wt % is the glass powder among the inorganicmaterials.

In forming a frit seal, a liquid material is added to the dry fritmaterial to form a frit paste. Any organic or inorganic solvent with orwithout additives can be used as the liquid material. In embodiments,the solvent includes one or more organic compounds. For example,applicable organic compounds are ethyl cellulose, nitro cellulose,hydroxylpropyl cellulose, butyl carbitol acetate, terpineol, butylcellusolve, acrylate compounds. Then, the thus formed frit paste can beapplied to form a shape of the seal 1071 on the top and/or bottom plate1061, 1002.

In one exemplary embodiment, a shape of the seal 1071 is initiallyformed from the frit paste and interposed between the top plate 1061 andthe bottom plate 1002. The seal 1071 can in certain embodiments bepre-cured or pre-sintered to one of the top plate and bottom plate 1061,1002. Following assembly of the top plate 1061 and the bottom plate 1002with the seal 1071 interposed therebetween, portions of the seal 1071are selectively heated such that the frit material forming the seal 1071at least partially melts. The seal 1071 is then allowed to resolidify toform a secure joint between the top plate 1061 and the bottom plate 1002to thereby inhibit exposure of the enclosed OLED pixel array 1021 tooxygen or water.

In embodiments, the selective heating of the frit seal is carried out byirradiation of light, such as a laser or directed infrared lamp. Aspreviously noted, the frit material forming the seal 1071 can becombined with one or more additives or filler such as species selectedfor improved absorption of the irradiated light to facilitate heatingand melting of the frit material to form the seal 1071.

In some embodiments, OLED devices 1011 are mass produced. In anembodiment illustrated in FIG. 7E, a plurality of separate OLED arrays1021 is formed on a common bottom substrate 1101. In the illustratedembodiment, each OLED array 1021 is surrounded by a shaped frit to formthe seal 1071. In embodiments, common top substrate (not shown) isplaced over the common bottom substrate 1101 and the structures formedthereon such that the OLED arrays 1021 and the shaped frit paste areinterposed between the common bottom substrate 1101 and the common topsubstrate. The OLED arrays 1021 are encapsulated and sealed, such as viathe previously described enclosure process for a single OLED displaydevice. The resulting product includes a plurality of OLED devices kepttogether by the common bottom and top substrates. Then, the resultingproduct is cut into a plurality of pieces, each of which constitutes anOLED device 1011 of FIG. 7D. In certain embodiments, the individual OLEDdevices 1011 then further undergo additional packaging operations tofurther improve the sealing formed by the frit seal 1071 and the top andbottom substrates 1061, 1002.

One problem of the organic light-emitting display device is that thedevice can be deteriorated when moisture contacts organic materialsconstituting the organic light-emitting elements. FIG. 1 is across-sectional view showing an encapsulation structure of an organiclight-emitting device that can prevent moisture from contacting organicmaterials. In the illustrated structure, the organic light-emittingdisplay device includes a deposition substrate 1, an encapsulationsubstrate 2, a sealing material 3 and a moisture-absorbing material 4.The deposition substrate 1, which is equivalent to the bottom plate1002, includes a pixel region including at least one organiclight-emitting diode or pixel, and a non-pixel region formed outside thepixel region, and the encapsulation substrate 2, which is equivalent tothe top plate 1061, is attached against a surface in which an organiclight-emitting diode of the deposition substrate 1 is formed.

In order to attach the deposition substrate 1 to the encapsulationsubstrate 2, the sealing material 3 is applied along edges of thedeposition substrate 1 and the encapsulation substrate 2, and thesealing material 3 is then cured using UV irradiation, etc. Amoisture-absorbing material 4 is included in the encapsulation substrate2 for the purpose of capturing moisture and certain gases such ashydrogen, oxygen. Even in the illustrated device, however, the sealingmaterial 3 may not completely prevent moisture or air entering into theenclosed space. Also, there may be cracks in the sealing material 3 andin the interfacial area where the sealing material 3 contacts thesubstrate for various reasons.

FIG. 2 is a simple plan view showing an organic light-emitting displaydevice according to an embodiment of the present invention; and FIGS. 3a and 3 b are cross-sectional views taken along a line A-A′ of FIG. 2.Referring to figures, the organic light-emitting display device includesa substrate 100, an encapsulation substrate 200, a frit 150 and areinforcement material 160. For the sake of convenience, the depositionsubstrate 101 refers to a base, on which circuits and layers are formed,and the substrate 100 refers to an unfinished product including thedeposition substrate 101 and circuits and layers formed thereon,including an array of organic light emitting pixels.

The substrate 100 is a plate including an organic light-emitting diodeor pixel, and includes a pixel region 100 a in which at least oneorganic light-emitting diode is formed, and a non-pixel region 100 bformed outside the pixel region 100 a, the organic light-emitting diodeincluding a first electrode 119, an organic layer 121 and a secondelectrode 122. Hereinafter, the pixel region 100 a is referred to as aregion for displaying a predetermined image using the light emitted froman organic light-emitting diode, and the non-pixel region 100 b isreferred to as the entire region except the pixel region 100 a on thesubstrate 100 in the description of this application.

The pixel region 100 a includes a plurality of scan lines (S1 to Sm)arranged in a horizontal direction, and a plurality of data lines (D1 toDm) arranged in a vertical direction, and a plurality of pixels areformed in the scan lines (S1 to Sm) and the data lines (D1 to Dm), thepixels receiving signals from a driver integrated circuit 300 fordriving organic light-emitting diodes or pixels. Also, a driverintegrated circuit (Driver IC) for driving an organic light-emittingdiode, and metal wirings electrically attached to each of the scan lines(S1 to Sm) and the data lines (D1 to Dm) of the pixel region are formedin the non-pixel region 100 b. In an embodiment, the driver integratedcircuit includes a data driving unit 170 and scan driving units 180,180′.

The organic light-emitting diodes or pixels are driven in an activematrix method, as shown in the drawings, and its configuration will bedescribed in brief. A buffer layer 111 is formed on a base substrate101, and the buffer layer 111 is formed of insulating materials such assilicon oxide (SiO₂) or silicon nitride (SiNx). The buffer layer 111prevents the substrate 100 from being damaged by factors such as heatfrom the outside, etc. On at least one region of the buffer layer 111 isformed a semiconductor layer 112 including an active layer 112 a and anohmic contact layer 112 b. On the semiconductor layer 112 and the bufferlayer 111 is formed a gate insulating layer 113, and on one region ofthe gate insulating layer 113 is formed a gate electrode 114 having asize corresponding to a width of the active layer 1112 a.

An interlayer insulating layer 115 includes the gate electrode 114 andis formed on the gate insulating layer 113, and source and drainelectrodes 116 a and 116 b are formed on a predetermined region of theinterlayer insulating layer 115. The source and drain electrodes 116 aand 116 b are formed so that they can be connected to one exposed regionof the ohmic contact layer 112 b, and an overcoat 117 includes thesource and drain electrodes 116 a, 116 b and is formed on the interlayerinsulating layer 115. A first electrode 119 is formed on one region ofthe overcoat 117, wherein the first electrode 119 is connected with oneexposed region of either one of the source and drain electrodes 116 aand 116 b by means of a via hole 118.

A pixel definition layer 120 includes the first electrode 119 and isformed on the overcoat 117, the pixel definition layer 120 having anopening (not shown) to which at least one region of the first electrode119 is exposed. An organic layer 121 is formed on the opening of thepixel definition layer 120, and a second electrode layer 122 includesthe organic layer 121 and is formed on the pixel definition layer 120.In an embodiment, a passivation layer may be further formed in an upperportion of the second electrode layer 122. In embodiments, variousmodifications and changes may be made in an active matrix structure or apassive matrix structure of the organic light-emitting device, and theirdetailed descriptions are omitted since each of the structures can beunderstood from the description of the invention by those skilled in theart.

An encapsulation substrate 200 is a member for encapsulating at leastone pixel region 100 a of the substrate in which the organiclight-emitting diode is formed, and is formed of transparent materialsin the case of top emission or dual emission and formed of translucentmaterials in the case of bottom emission. Various materials of theencapsulation substrate 200 can be used, for example, a glass may beused in an embodiment, for example in the case of the top emission,although not limited thereto.

The encapsulation substrate 200 is formed in a plate shape in anembodiment, and encapsulates a pixel region in which the organiclight-emitting diode is formed on at least the substrate 100. Forexample, the entire region is encapsulated except a data driving unitand a pad unit in an embodiment. The frit 150 is formed between theencapsulation substrate 200 and the non-pixel region 100 b of thesubstrate 100 to seal the pixel region 100 a so that the air or anyfluid is prevented from passing through or being infiltrated. In anembodiment the frit 150 forms a line spaced apart at a constant distancefrom an edge of an interface in which the encapsulation substrate 200and the substrate 100 are coalesced to each other. This is to secure aspace that forms a reinforcement material 160, as described later, and aspaced distance ranges from about 0.3 to about 0.7 mm. In an embodiment,the frit 150 includes a glass material, a moisture-absorbing materialfor absorbing a laser, a filler for reducing a thermal expansioncoefficient, etc., and is applied to the encapsulation substrate 200 ina state of frit paste, melted and cured in an interface between theencapsulation substrate 200 and the substrate 100 using a laser or aninfrared ray to seal the interface between the encapsulation substrate200 and the substrate 100. In an embodiment, the line in which the frit150 is formed has a width of about 0.5 to about 1.5 mm.

Meanwhile, in an exemplary embodiment, configurations and materials of asurface of the substrate 100 with which the frit 150 is in directcontact can be used although not limited thereto. In an embodiment, thefrit is not overlapped with a metal wiring as possible as it is, excepta period of a metal wiring directly connected with a driver integratedcircuit, although not limited thereto. If the frit 150 is overlappedwith the metal wiring, the metal wiring may be damaged due toirradiation of a laser or an infrared ray. In an embodiment, areinforcement material or structure 160 is formed in an outer side ofthe line of the frit 150. In an embodiment the reinforcement material160 may prevent an organic light-emitting display device from beingdamaged or broken, and function as a sealing material if the frit 150 isnot attached or its adhesive force is reduced when it is deliquesced byother materials. The reinforcement material 160 can be formed spacedapart at a predetermined distance form the frit 150, or formed adjacentto the frit 150. In an embodiment, the reinforcement material 160 formedin the outside of the frit 150 may be formed in a gap between thesubstrate 100 and the encapsulation substrate 200, and side surfaces ofthe substrate 100 and the encapsulation substrate 200, as shown in FIG.3 a. In another embodiment, the reinforcement material 160 may be alsoformed only in a gap between the substrate 100 and the encapsulationsubstrate 200, as shown in FIG. 3 b.

In an embodiment, curable materials, which are naturally cured,thermally cured or UV-cured, may be used. Liquid materials can be usedfor forming the reinforcement material or structure 160. For example,cyanoacrylate may be used as the naturally cured material; acrylate maybe used as the material that is thermally cured at a temperature ofabout 80° C. or less; and epoxy, acrylate and urethane acrylate may beused as the UV-cured materials.

Hereinafter, embodiments of a method for packaging an organiclight-emitting display device according to the present invention will bedescribed in detail. FIGS. 4 a to 4 d are process views showing aprocess for preparing an organic light-emitting display device. Firstly,a frit 150 is applied in a linear shape in a point spaced apart at apredetermined distance from an edge of an encapsulation substrate 200,and the frit 150 is formed in a point corresponding to a non-pixelregion 100 a of the substrate 100, as described later. In an embodiment,the height of the frit 150 ranges from about 10 to about 20 μm. The frit150 is applied to the encapsulation substrate 200 at a state of the fritpaste, sintered to remove moisture or organic binders that are allincluded in the paste, and then cured. (See FIG. 4 a)

In an embodiment, a substrate 100 including a pixel region including anorganic light-emitting diode, and a non-pixel region in which a driverintegrated circuit and a metal wiring, etc. are formed is provided, andan encapsulation substrate 200 is coalesced. (See FIG. 4 b) Next, alaser or an infrared ray is irradiated to the frit 150 between thesubstrate 100 and the encapsulation substrate 200, both coalesced toeach other, to melt the frit 150 between the substrate 100 and theencapsulation substrate 200. In an embodiment, the irradiated laser orinfrared ray, used herein, has, for example, a wavelength of about 800to about 1200 nm (and in another embodiment, about 810 nm), its powerranges from about 25 to about 45 watt. In an embodiment, the regionexcept the frit is masked. Layers of cooper and aluminum may be used asmaterials of the mask. The substrate 100 and the encapsulation substrate200 are attached to each other by curing the melted frit 150. (See FIG.4 c)

In an embodiment, subsequently to the formation of the frit, areinforcement material or structure 160 is formed in a gap between thesubstrate 100 and the encapsulation substrate 200, and side surfaces ofthe substrate and the encapsulation substrate. In an embodiment, gapsexist in the sides of the substrate 100 and the encapsulation substrate200 since the frit 150 is not formed adjacent to the edges, but formedspaced apart at a predetermined distance from the sides of thesubstrates. The liquid material for reinforcement material 160 isapplied to or injected into the edge regions or sides by using adispenser, and then cured. In an embodiment, the gap between thesubstrate 100 and the encapsulation substrate 200 is identical to theheight of the frit such that, when a liquid for the reinforcementmaterial is supplied on the sides or edges, then the liquid can be movedinto gaps by a capillary phenomenon, and then cured. (See FIG. 4 d) Inan embodiment, the material which formed on the side surface of thesubstrate 100 and the encapsulation substrate 200 may be optionallyremoved. In an embodiment, if the materials of the reinforcementmaterial 160 are naturally cured, then preparation of an organiclight-emitting device is completed without an additional process. Inanother embodiment, if the materials of the reinforcement material 160are UV-cured, then there is required an additional process for maskingand irradiating the reinforcement material 160 with UV ray. In anembodiment, and if the materials of the reinforcement material 160 arethermally cured, then there is required an additional process forsubjecting the heat to the reinforcement material.

The aforementioned method is the method used when an organiclight-emitting display device is prepared in a unit cell. In anembodiment, a method in which a plurality of organic light-emittingdisplay devices is prepared may be provided, which will be describedwith reference to FIGS. 5 a to 5 e. In an embodiment, a frit paste 350is applied onto a mother plate 400, from which a plurality ofencapsulation substrates are formed, at positions spaced apart fromimaginary lines which will be edges of portions which are formed intoeach of the encapsulation substrates. In an embodiment, the frit paste350 includes a glass material, a laser-absorbing material, a filler forreducing a thermal expansion coefficient, an organic binder, etc. In anembodiment, the frit paste is sintered at a temperature of approximately400 to 600° C. after the frit paste is applied thereto, wherein theorganic binder or moisture, etc. are evaporated in the sinteringprocedure. (See FIG. 5 a)

Subsequently, the encapsulation substrate mother plate 400 in which thefrit 350 is sintered is coalesced to a substrate mother plate 300prepared separately. (See FIG. 5 b) Subsequently, the substrate motherplate 300 and the encapsulation substrate mother plate 400 are attachedto each other by irradiating a laser or an infrared ray to the frit 350formed between the substrate mother plate 300 and the mother plate 400of the encapsulation substrate. In an embodiment, the irradiated laseror infrared ray has, for example, a wavelength of about 810 to about1200 nm, its power ranges from about 25 to about 45 watt, a region wherethe laser or infrared ray may be irradiated is masked, and the laser orinfrared ray may be irradiated in a direction toward the encapsulationsubstrate, the substrate, or in both directions. In embodiments, theinsides of the substrate and the encapsulation substrate are maintainedat a lower pressure than an atmospheric pressure when the substrate andthe encapsulation substrate are coalesced to each other. (See FIG. 5 c)

In the illustrated embodiment, subsequently, the substrate mother plate300 and encapsulation substrate mother plate 400 which are coalesced toeach other are scribed or cut into a plurality of separate displaydevices, and organic light-emitting display devices may be prepared byapplying a reinforcement material 360 to the side surfaces of thedisplay devices by using a dispenser. (See FIG. 5 d) In one embodiment,only the encapsulation substrate may be scribed, the separateencapsulation substrate is coalesced to correspond to only a certainregion of the substrate.

Hereinafter, another embodiment of an organic light-emitting displaydevice according to the present invention will be described in detail.An encapsulation substrate 600 used in this embodiment does not have ausual plate shape, but a cap shape, and therefore the encapsulationsubstrate 600 will be described in brief on the basis of parts differentto the other embodiments discussed above. If a capped encapsulationsubstrate 600 is used, then the amount of frits 550 to be used may bereduced and the time needed to melt the frit 550 by irradiating a laseror an infrared ray may be also shortened.

In the illustrated embodiment, the encapsulation substrate 600 includesan encapsulation unit 610 and a spacer unit 620. The encapsulation unit610 is an encapsulation plate corresponding to an organic light-emittingunit in which organic light-emitting diodes of the substrate 500 isformed, and the spacer unit 620 may separate the substrate 500 and theencapsulation substrate 600 apart at a predetermined distance. In anembodiment, the frit 550 is formed on the spacer unit 620, and appliedin a linear shape at a position spaced apart with a predetermineddistance from an edge toward the inner side, and then cured.

The spacer unit 620 of the encapsulation substrate 600 and the substrate500 are coalesced to each other, and then the encapsulation substrate600 and the substrate 500 are attached to each other by irradiating alaser or an infrared ray to the frit 550 formed on the spacer unit 620.In an embodiment, a liquid of a reinforcement material 560 is applied togaps between the substrate 500 and the spacer unit 620 of theencapsulation substrate 600 outside the frit 550, and the liquid of thereinforcement material 560 moves into gaps by a capillary phenomenon.

The present invention has been described in detail with reference toembodiments. However, it would be appreciated that modifications andchanges might be made to the embodiments without departing from theprinciples and spirit of the invention. For example, modifications andchanges may be made in a method for forming a reinforcement material,and a position of a reinforcement material.

Although a few embodiments of the present invention have been shown anddescribed, it would be appreciated by those skilled in the art thatchanges might be made in the embodiments without departing from theprinciples and spirit of the present invention, the scope of which isdefined in the claims and their equivalents.

What is claimed is:
 1. An organic light-emitting display device,comprising: a first substrate, wherein the first substrate comprisesglass; a second substrate placed over the first substrate, wherein thesecond substrate comprises glass; an array of organic light-emittingpixels interposed between the first and second substrates; a frit sealinterposed between the first substrate and the second substrate whilesurrounding the array, wherein the frit seal, the first substrate andthe second substrate in combination define a substantially enclosedspace in which the array is located; and a structure interposed betweenthe first and second substrates, wherein the structure is interposedonly between the first and second substrates, wherein the structurecontacts the frit seal along an entire outer perimeter of the frit sealto surround the frit seal, wherein the frit seal surrounds the array,and wherein the structure improves structural strength of the device andsealing of the enclosed space, wherein the structure comprises apolymeric resin.
 2. The device of claim 1, wherein the portion of thestructure contacts the frit seal.
 3. The device of claim 1, wherein thestructure comprises at least one selected from the group consisting ofcyanoacrylate, acrylate, epoxy, acrylate, urethane acrylate and curedpolymers of two or more of the foregoing.
 4. The device of claim 1,wherein the frit seal is connected to the first substrate via a materialformed between the frit seal and the first substrate.
 5. The device ofclaim 1, wherein the structure contacts the first substrate.
 6. Thedevice of claim 1, wherein the structure is connected to the firstsubstrate via another material between the structure and the firstsubstrate.
 7. The device of claim 1, wherein the first substratecomprises a first edge and the second substrate comprises a second edgeextending generally along the first edge, and wherein the frit sealextends along the first and second edge while apart from the first andsecond edges, wherein the structure contacts the first and secondsubstrates and extends along the first and second edges.
 8. The deviceof claim 7, wherein the structure continuously contacts the first andsecond edges.
 9. The device of claim 1, wherein the first substratecomprises a first edge and the frit seal is apart from the first edgefrom about 0.3 to about 0.7 mm.
 10. The device of claim 1, wherein thefirst substrate comprises a front surface of the device, the frontsurface facing away from the second substrate, and wherein the structureprovides a side surface of the device.
 11. The device of claim 10,wherein the first substrate comprises a first edge and the secondsubstrate comprises a second edge extending generally along the firstedge and wherein the side surface extends continuously along the firstand second edges and is substantially planar.
 12. The device of claim 1,wherein the frit seal comprises one or more materials selected from thegroup consisting of magnesium oxide (MgO), calcium oxide (CaO), bariumoxide (BaO), lithium oxide (Li₂O), sodium oxide (Na₂O), potassium oxide(K₂O), boron oxide (B₂O₃), vanadium oxide (V₂O₅), zinc oxide (ZnO),tellurium oxide (TeO₂), aluminum oxide (Al₂O₃), silicon dioxide (SiO₂),lead oxide (PbO), tin oxide (SnO), phosphorous oxide (P₂O₅), rutheniumoxide (Ru₂O), rubidium oxide (Rb₂O), rhodium oxide (Rh₂O), ferrite oxide(Fe₂O₃), copper oxide (CuO), titanium oxide (TiO₂), tungsten oxide(WO₃), bismuth oxide (Bi₂O₃), antimony oxide (Sb₂O₃), lead-borate glass,tin-phosphate glass, vanadate glass, and borosilicate.